Method and apparatus for shaving wire

ABSTRACT

THIS INVENTION RELATES TO A METHOD AND APPARATUS FOR SHAVING TITANIUM WIRE. MORE PARTICULARLY, THE INVENTION RELATES TO A PRACTICE FOR ELIMINATING PROCESSING AND QUALITY DIFFICULTIES ENCOUNTERED IN THE SAVING OF TITANIUM WIRE TO PRODUCE, IN PARTICULAR, A WIRE OF SUPERIOR SURFACE QUALITY. THIS IS ACHIEVED BY THE OPERATION OF COLD WORKING SAID WIRE PRIOR TO SHAVING, USING A LOW VISCOSITY (50 TO 150 SUS AT 100*F.) CUTTING OIL AND A RAKE ANGLE OF BETWEEN ABOUT 5 TO 12 DEGREES BETWEEN THE DIE AND THE WIRE DURING SHAVING. THE WIRE IS SHAVED WHILE TRAVELING AT A SPEED UP TO 150 FEET PER MINUTE. THE CHIPS SHAVED FROM THE WIRE DURING THIS OPERATION ARE CONTINUOUSLY REMOVED.

- Ja'fi. 26,1971 J.P.CA TLIN-ETAL 3,557,588

METHOD AND APPARATUS FOR sH vING WIRE Filed April 18,1968

70 Oil-1n INVENTORS.

JOHN R cATL/A/ and TED l-l. W/D/VER Ar farney United States Patent 3 557 588 METHOD AND APPAI QAT US FOR SHAVING WIRE John P. Catlin, Beaver, and Ted H. Widener, Pittsburgh,

Pa., assignors to Crucible Inc., a corporation of Delaware Filed Apr. 18, 1968, Ser. No. 722,270 Int. Cl. B21b 45/02 U.S. C]. 72-45 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a method and apparatus for shaving titanium wire. More particularly, the invention relates to a practice for eliminating processing and quality difficulties encountered in the shaving of titanium wire to produce, in particular, a wire of superior surface quality. This is achieved by the operation of cold working said wire prior to shaving, using a low viscosity (50 to 150 SUS at 100 F.) cutting oil and a rake angle of between about to 12 degrees between the die and the wire during shaving. The wire is shaved while traveling at a speed up to 150 feet per minute. The chips shaved from the wire during this operation are continuously removed.

In the manufacture of titanium alloy wire, for uses such as fastener stock, it is necessary to remove an oxide film and other surface defects from the wire surface as a final processing step. This operation is typically performed by a series of grinding steps. Grinding to remove the oxide layer is disadvantageous in that a number of separate grinding operations are necessary to achieve satisfactory removal of the surface layer, and the operation is relatively slow, in that during grinding the wire is moved through the grinder at a speed of only about 8 to 12 feet per minute. In the production of stainless steel wire and carbon steel needle wire, it is known to atv least partially replace grinding practice by a single shaving operation. In this practice, the wire is pulled through a shaving die, whereby the surface layer is removed by a single shaving operation. Although, in the production of titanium alloy wire, this shaving practice would have obvious advantage, prior to the present invention it could not be commercially employed as a replacement for a series of grinding steps because wire of satisfactory surface quality could not be produced by shaving. With titanium alloy wire, a shaving operation to remove the surface layer conventionally resulted in a final product of. poor surface quality. Specifically, the Wire surface contained irregularities or roughened areas and eccentric metal removal, presumably caused by irregular movement of the wire through the shaving die. Therefore, prior to the present invention, titanium alloy wire could not be successfully processed by a shaving operation but instead was subjected to more costly and time-consuming grinding operations as discussed herein.

It is accordingly an object of the present invention to provide a method and apparatus for shaving titanium alloy wire that will produce wire of acceptable'surface quality in less time and at a lower cost than that resulting from the use of conventional grinding. In accordance with the present invention, this is achieved by first passing titanium alloy wire to be shaved through a draw or sizing die. The sizing die serves to cold work the wire and also functions to dampen vibrations by achieving a'reduction of the wire diameter. During the sizing operation, high pressure lubrication is desired to enhance the vibration-dampening effect of the sizing operation. In the absence of the dampening effect, the wire will vibrate during passage through the shaving die, which impairs the surface quality of the wire. To achieve the required lubrication, a second die is provided behind the sizing die. This second die has an inside diameter larger than the wire diameter. This inhibits lubricant removal from the area of the sizing die and thus maintains the lubricant at the desired high pressure within this area.

After sizing, and prior to entering the shaving die,

the wire passes through a guide bushing that functions to center the wire with respect to a shaving die. The guide bushing has a bore about 0.003 inch larger than the wire diameter as it leaves the sizing die. The shaving die has an inside diameter of about 0.01 inch smaller than the diameter of the wire entering the die. Hence, this amount of surface is typically, in the practice of the present invention, removed from the wire by the die. Conventional tungsten-carbide shaving dies have been found suitable. To obtain the desired smooth, shaved finish on the wire after shaving, the die must be supplied, during shaving, with a low-viscosity cutting oil. For this purpose, the cutting oil is typically at a pressure of approximately 1000 psi. when applied at the shaving die and should have a viscosity within the range of 50 to 150 SUS at F. To maintain this pressure, a special oil-bleed bushing is employed behind the die and serves to direct the high-pressure cutting oil at the desired high pressure to the interior shaving surface of the die. This bushing will be described in greater detail hereinafter. In addition, the rake angle between the die and the wire being shaved should be about 5 to 12 degrees. It is also necessary that the wire during shaving be traveling at a speed of up to 15 0 feet per minute and preferably within the range of 20 to feet per minute. Further, the shaved wire leaving the shaving die should be free from metal contact. If all of these conditions are not maintained, the surface of the wire will become marked or roughened during shaving and the desired smooth, shaved wire surface will not be obtained.

Additional factors that favorably affect the surface quality of the shaved wire are the continuous removal of the chips as they are shaved from the wire by the die and the use of a relatively cool cutting oil or lubricant. The cutting lubricant when introduced to the shaving surface of the die should be at a maximum temperature of about 150 F. The apparatus employed for removing the chips as they are shaved from the wire will be described in greater detail hereinafter.

In the operation of the wire shaving apparatus, it is necessary to frequently remove the shaving die for replacement of the cutting inserts if good shaving action is to be maintained. It is advantageous to perform this die-removal operation quickly to minimize apparatus downtime and thereby preserve the economy of operation over conventional wire grinding machines caused by increased operating speed. For this purpose, the shaving apparatus is designed for quick unitary removal of the shaving die unit. Upon the removal of a cap on the end of the shaving head, the entireshaving die unit slides axially from the shaving head. A new shaving die is then inserted, and the entire unit is inserted axially into the shaving head. Upon replacementof the threaded end generally as 10, mounted on a tray 12 anchored to a mounting bracket 14, which serves to secure the apparatus to a suitable base not shown. The wire shaving apparatus consists of a sizing wire-drawing head, which is designated generally as 16, and a wire shaving head, which is designated generally as 18. Wire to be shaved, which is designated as W, passes in the direction of the arrow as shown in FIG. 1, through the sizing unit 16 and then through the axially aligned shaving head 18. The unit 16 is of generally rectangular cross section and includes a reservoir 20 containing a supply of powdered drawing lubricant. The wire W to be shaved enters the lubricant-containing reservoir 20 through a lead bushing 22. The lead bushing 22 serves to align the wire with respect to a lead die 24 that is axially aligned with the lead bushing 22 and a sizing draw die 26. The dies are secured by a die holder 28 against a mounting plate 30. The die 24 has an inside diameter about 0.050 inch greater than the diameter of the wire passing through the die. This permits lubricant from the reservoir 20 to enter the area 29 of the die 26, which is between this dis and the die 24. It is understood that no drawing action is produced by the die 24. The lubricant within area 29 is confined therein under pressure caused by the continuous supply of lubricant to this area with the wire passing through the die 24. In this manner, the high lubricity required at the die 28 to dampen vibration of the wire during the subsequent wire-shaving operation is achieved.

The wire shaving die head 18 contains a guide bushing 32 that aligns the wire W to be shaved with shaving die 34. The guide bushing 32 is secured by a retaining collet 36. The retaining collet 36 is in threaded engagement, as at 38, with a draw bar 40. This structure is supported by block 42 that is secured by nut 44, which is in threaded engagement, as at 46, with a support sleeve 48 that provides a housing for the draw bar 40, the retaining collet 36 and the guide bushing 32.

The shaving die 34, which is axially aligned with the guide bushing 32, is contained within an annular holder 50. The holder 50 in combination with an oil distributor disk 52 secure the wire shaving die 34 in position for shaving, as shown in the drawings. The disk 52 has a center axial opening 54 that is axially aligned with the opening in shaving die 34. In addition, the disk 52 contains a series of cutting-oil passages 56, which serve to direct cutting oil from a high-pressure cutting-oil source to the area of shaving contact between said shaving die and wire. To the right of disk 52, as viewed in the drawings, and axially aligned therewith is an oil-bleed bushing 58. The bushing 58 has an exterior, annular relieved portion 60 defining a high-pressure cutting-oil collecting zone communicating with the passages 56 of the disk 52. The oil-bleed bushing 58 is surrounded by an oil distributing bushing 62 having oil distribution passages 64. The passages 64 communicate with the relieved portion 60, or cutting-oil collecting zone, of the oil-bleed bushing 58. This structure is housed within a shaving head supporting block 66 having a drilling 68 communicating at one end with cutting-oil passage 64 of the oil distributing bushing and at the other end with a passage 70 within a cutting-oil inlet cap 74. The passage 70 of the inlet cap 74 is connected to a suitable source of high-pressure cutting oil (not shown). The block 66 contains a relatively larger cutting-oil passage 76 communicating with an end of the oil-bleed bushing 58. The passage 76 serves to remove the cutting oil to a suitable cooling arrangement (not shown). To the right of the oil distributing bushing 62, as viewed in FIG. 1 of the drawings, is positioned a gland 78. Within the gland 78 an exit bushing 80 is axially mounted. The components 78 and 80 are secured by a locking nut 82 that is in threaded engagement, as at 84, with block 66. The wire exits from the unit through a rear bushing retainer plug 86' that is in threaded engagement, as at 88, with component 82.

During the operation of the shaving head, it is necessary to frequently replace the shaving die 34. With the apparatus as described hereinabove and shown in the drawings, this may be achieved extremely rapidly by merely unscrewing locking nut 82. Upon the removal of nut 82, the unitary removal of the shaving die 34 with components '50, 52, 58, 62 and 78 may be achieved by sliding these components as a unit axially and to the right, as viewed in FIG. 1 of the drawings, until the shaving die .34 is removed from the block 66. The die 34 may then be replaced with a new die and the entire unit again inserted into position, as shown in FIG. 1, for shaving. Upon the replacement of locking nut 82, the unit is ready for further operation.

In the operation of the apparatus shown in the drawings and described hereinabove, the wire W moving in the direction of the arrow passes into the sizing die unit 16. It passes through the reservoir 20 wherein it contacts the dry powdered lubricant, which serves to provide the lubricity required for the sizing operation which is performed by draw die 28. Any suitable conventional powdered soap-type lubricant typically used in wire drawing operations may be used in the reservoir 20 for lubricating the wire prior to drawing through die 28.

The wire having been subjected to the sizing operation, during which a reduction in diameter is achieved, next enters the wire shaving head 18. The wire enters this unit through the draw bar 40 whereby it is guided by the guide bushing 32 into shaving engagement with the shaving die 34. During the shaving operation, high-pressure, lowviscosity lubricant is supplied to the area of shaving contact between the die and the wire via passages 56 in the disk 52. The cutting oil is maintained at high pressure at this area by means of bushing 58. After shaving, the wire passes through the restricted axial opening of the bleed bushing. Since the wire diameter is only slightly smaller than the diameter of the bushing interior, such acts to substantially restrict the lubricant flow through the bushing with the wire and thus serves to maintain the cutting oil at high pressure adjacent the cutting surface of the shaving die 34. As the lubricant leaves the end of the bushing 58, it is conveyed, via passage 76, to means for cleaning and cooling the lubricant (not shown). During the shaving operation, it is typical to remove about 0.01 inch from the wire surface as it is pulled through the shaving die 34. This is sufiicient to remove the surface layer on the wire and provide the desired smooth wire finish.

As the wire is moving through the shaving die 34, cutting chips or shavings indicated as C, are continuously produced at the shaving die. It has been found that if these chips are not continuously removed, they will cause clogging of the die and marking or abrading of the wire surface. To permit removal of these chips, the unit 18 is preferably provided with a rotating chip breaker designated generally as 90. The chip breaker 90 consists of a plurality of equally spaced cutting blades 92 that rotate about an axis coincident with that of the wire being shaved. The blades are connected to a ring 94 having on its exterior circumferentially spaced teeth 96. The interior of the ring 94 is in rotating engagement with a plurality of cylindrical roller bearings 98. As best shown in FIG. 2 of the drawings, the exterior teeth 96 are connected to a continuous belt that is in turn drivingly connected to a suitable driving means, such as an electric motor (not shown), that drives the belt to in turn rotate the cutter 90 and associated cutting blades 92. As the cutting blades 92 rotate about an axis coincident with that of the wire, any shavings C from the wire, which tend to progress radially from the die axis, are chopped into small pieces by the cutting blades and are thus prevented from fouling the shaving die 34. In this manner, the desired smooth wire surface achieved during shaving is preserved.

It should be noted, and as may be seen from FIG. 1, the shaved wire after leaving the shaving die 34 is maintained substantially out-of-contact with the interior surfaces of bushing 62, gland 78, bushing and plug 86, through which the shaved wire passes. Any substantial metal contact of the shaved titanium wire with the components of the apparatus wire cause surface abrasion of the wire.

In the practice of the invention wire of various compositions-including 6 percent aluminum, 4 percent vanadium and balance titanium, 11.5 percent molybdenum, 6 percent zirconium, 4.5 percent tin and balance titanium and commercially pure titaniumwas shaved. During these wire-shaving operations, about 0.10 to 0.012 inch of metal was removed from the wire surface. The diameter of the wire varied widely but was typically within the range of to inch. During these shaving trials various operating conditions as discussed herein were tried. To produce titanium or titanium alloy wire of the desired surface quality, it was found that the operating limits and conditions as discussed herein were significant.

To achieve successful shaving by the method and apparatus as described hereinabove, it is necessary that the wire be subjected to cold working of at least about 0.002

inch reduction prior to shaving. This is necessary to insure the production of a smooth shaved surface. Also required for this purpose is that the lubricant when directed under high pressure to the cutting area of the shaving die be cooled to a temperature not higher than 150 F, and preferably within the range of about 80 to 100 F. The lubricantviscosity must be within the range of 50 to 150 SUS at 100 F. The pressure of the lubricant at the shaving area of the die should be approximately 1000 p.s.i. Further, to prevent marking of the wire surface during shaving, the wire shaving speed should be no greater than 150 feet per minute and preferably within the range of 20 to 150 feet per minute. The rake angle of the die should be about to 12 degrees.

If the lubricant viscosity is too high, it is difiicult to get the lubricant to the cutting edge of the shaving die where itis needed to provide for efficient shaving action. A suitable lubricant or cutting oil for use in the practice of the invention is Garia oil H2 percent sulfur. An improper rake angle has been found to result in not only a roughening of the shaved wire surface, but in addition has been found to adversely affect the symmetry of the surface removal from the wire. At wire shaving speeds below feet per minute, the wire vibrates as it progresses through the shaving die. This vibrating action causes a marking of the wire surface. At line speeds greater than about 150 feet per minute, the tool wear becomes excessive, although these high speeds have not been found to be detrimental with respect to the surface quality of the wire. The lubricant temperatures as set forth above are necessary to maintain the required lubricity necessary for effective shaving.

The apparatus has found success in the shaving of wire having diameters ranging from about 7 to about of an inch. The shaving edge of the shaving die may be constructed from a tungsten-carbide material.

The term titanium wire as used herein is intended to include wire of titanium or equivalent alloys that are substantially equivalent in behavior in wire shaving in accordance with the invention.

Although a specific example of the invention has been shown and described herein, it is obvious that other adaptations and modifications may be made without departing from the scope and spirit of the appended claims.

What is claimed is:

1. Apparatus for shaving titanium wire comprising means for cold working said wire immediately prior to shaving, said cold-working means including a first die having an inside diameter greater than said wire diameter and said first die being positioned adjacent a second die having an inside diameter smaller and than said wire diameter and adapted to cold work said wire as it is pulled through said second die, means for centering said wire with respect to a shaving die having a rake angle of about 5 to 12 degrees, means for moving said wire through said shaving die for shaving at a speed of about 20 to feet per minute, means for introducing a lowviscosity cutting oil to an area of shaving contact between said wire and said shaving die including means for introducing said cutting oil under high pressuer to a highpressure collecting zone, means for distributing said cutting oil from said collecting zone under high pressure substantially uniformly along the shaving area of said shaving die, said high cutting oil pressure being maintained by a restricted passage through which saidshaved wire and cutting oil are conveyed to a low-pressure zone from said area of shaving contact of said die and means for continuously removing chips resulting from said shaving operation.

2. The apparatus of claim 1 wherein said restricted passage is adapted and aligned to guide said shaved wire axially with respect to said shaving die.

3. The apparatus of claim 1 wherein said restricted passage for said shaved wire is a bushing having an exterior relieved portion defining said high-pressure collecting zone.

4. The apparatus of claim 3 wherein said means for distributing said cutting oil from said high-pressure collecting zone includes a disk interposed between said shaving die and said bushing and having an axial opening communicating with said bushing through which said shaved wire passes and a plurality of cutting-oil passages extending between said high-pressure collecting zone and the shaving area of said shaving die.

5. The apparatus of claim 1 wherein said means for continuously removing chips resulting from said cutting operation includes a rotating cutter, which rotates about an axis coincident with the axis of said wire and cuts said chips into shorter lengths.

6. The apparatus of claim 5 wherein said rotating cutter includes a plurality of rotating cutter blades against which said chips impinge as they are shaved from the wireand are thereby cut into shorter lengths and removed.

References Cited UNITED STATES PATENTS 2,233,928 3/1941 Weaver 2933 2,896,310 7/1959 Young 2995.1 2,252,365 8/1941 P. Fisher 7241 2,510,298 7/ 1950 Schinnerer 2995.1 3,093,897 7/1963 Lemyre 72275 3,055,102 9/1962 Shaw 72275 2,679,680 6/1954 Hanks 2995.1 3,055,102 9/1962 Shaw 72-2.75 3,145,832 8/1964 Case 7243 FOREIGN PATENTS 908,063 10/ 1962 Great Britain 72275 977,988 12/ 1964 Great Britain 82-923 CHARLES W. LANHAM, Primary Examiner A. L. HAVIS, Assistant Examiner U.S. Cl. X.R. 

